Enteral nutrition in the hemodynamically unstable critically ill patient.

The benefit of enteral nutrition in critically ill patients has been demonstrated by several studies, especially when it is started early, in the first 24-48h of stay in the Intensive Care Unit, and this practice is currently advised by the main clinical guidelines. The start of enteral nutrition is controversial in patients with hemodynamic failure, since it may trigger intestinal ischemia. However, there are data from experimental studies in animals, as well as from observational studies in humans that allow for hypotheses regarding its beneficial effect and safety. Interventional clinical trials are needed to confirm these findings.

Contralateral extraaxial hematomas after urgent neurosurgery of a mass lesion in patients with traumatic brain injury.

PURPOSE: The development of a contralateral extraaxial hematoma has repeatedly been described in small series and descriptive studies. However, the evidence available to date is limited. OBJECTIVES: To evaluate the incidence and risk factors leading to the development of a contralateral extraaxial hematoma and to describe the characteristics of cases. METHODS: A retrospective cohort study with prospective data collection was undertaken. All patients admitted to an intensive care unit (ICU) from 2006 to 2010 were studied. The inclusion criteria were as follows: severe trauma [Injury Severity Score (ISS ≥ 16)], neurosurgery (NeuroSx) in the first 24 h. The following were excluded: subacute/chronic subdural hematomas, first bilateral NeuroSx. Cases were those who required immediate contralateral NeuroSx after the first NeuroSx due to the occurrence of a new extraaxial injury or significant growth of a previous one. Controls were those patients those who did not require second NeuroSx or who required reoperation due to ipsilateral lesions. The variables considered were: demographics, neurological assessment, traumatic injuries and severity, image and surgical findings, clinical course, and outcome. Statistics analysis comprised descriptive, inferential, and multivariate analysis by logistic regression. RESULTS: A total of 120 patients were included, among which there were 11 cases (incidence 9.2 %). The cases showed a significantly higher frequency of coma or severe traumatic brain injury (TBI) at admission, contralateral injury and contralateral skull fracture in the preoperative computed tomography (CT) scan, as well as decompressive craniectomy. There were no significant differences in the severity scores, clinical course, or outcomes. The presence of contralateral fracture was identified as an independent risk factor [relative risk (RR) 47.9, 95 % confidence interval (CI) 5.2-443]. CONCLUSIONS: Contralateral extraaxial hematoma is a rare entity, although it has a high mortality rate. Therefore, it requires a high index of suspicion, especially in patients with severe TBI, with minimal contralateral injury and mainly with contralateral skull fracture on the initial CT scan.

Fracturas de cadera del anciano / No disponible

No disponible

Estudio clínico de la osteosíntesis intra y extramedular en las fracturas trocantéreas de cadera / Clinical study of intramedullary and extramedullary osteosynthesis in trochanteric fractures of the hip

Se ha realizado un estudio comparativo de las fracturas trocantéreas tratadas con sistema extramedular modelo placa con tornillo-deslizante DHS de AO (Synthes®) y sistema intramedular modelo clavo Gamma de 2ª generación (Howmedica®) desde 1996 hasta julio de 1998. Se trata de un estudio retrospectivo de 95 pacientes tratados con ambos sistemas (56 pacientes con Gamma y 39 con DHS), sobre un total de 250 historias clínicas revisadas. El objeto de este estudio clínico ha sido el corroborar en la clínica los resultados biomecánicos observados en el estudio de ambas técnicas mediante elementos finitos. Con relación al sistema DHS, el clavo Gamma consigue resultados similares en las fracturas estables. En las fracturas inestables, el clavo Gamma permite una reanudación más precoz de la marcha. Las dificultades y los errores técnicos determinan con el clavo Gamma estático una mayor incidencia de complicaciones en la evolución del tornillo cefálico (AU)

Experimental model of multidirectional disc hernia in rats.

We have carried out an experimental investigation of lesions of the intervertebral disc produced by flexion, lateral bending and rotational forces in an attempt to produce disc herniations. Adult Wistar rats were divided into 4 groups: control and posterior, lateral and rotational herniation. There were 10 rats in each group. The tail between the 5th and 8th vertebral segments was used. A Kirschner wire was inserted into each of 2 adjacent vertebrae and the movement produced had an apex which was anterior or lateral depending on the group involved. Variables such as rupture of the annulus, the cellularity of the nucleus pulposus and the site of the lesion in the disc were studied histologically. The height of the disc, the protrusion, the thickness, and the surfaces of the annulus fibrosus and the nucleus pulposus were measured. In every case we found a nuclear displacement which did not become a protrusion. The surface parameters and the cellularity of the nucleus pulposus are most useful indicators and should be included in any study examining the disc after the injection of substances for treatment.

Effects of aerobic and anaerobic physical conditioning on fibrinolysis.

The effects of aerobic and anaerobic physical conditioning on fibrinolysis were studied before and immediately after physical exercise. Moderately active controls (group A) were compared with aerobically- (group B) or anaerobically-conditioned (group C) subjects. Comparison of the resting parameters revealed that FgDP were significantly higher in group B as a compared to groups A and C. FbDP did not significantly differ between groups B and C and were significantly lower in group A. t-PA antigen and PAI antigen did not significantly differ between the three groups, but t-PA activity was elevated and PAI activity and t-PA/PAI complexes were reduced in group B. Following a maximal exercise test on the treadmill both FbDP and FgDP were significantly increased in all groups, although values for FbDP in group B and values for FgDP in group C reached a higher level than in group A. t-PA antigen and t-PA activity were also increased in the three groups. PAI activity was significantly reduced in groups A and C. t-PA/PAI complexes were significantly enhanced in all cases, but increased to a lower degree in group B. These results indicate that both aerobic and anaerobic physical conditioning induce activation of the fibrinolytic system.

Effects of oral contraceptives on fibrinolytic response to exercise.

In this study the influence of low-dose oral contraceptives (OC) on the different components of the fibrinolytic system before and immediately after maximal exercise was examined in a group of 18 moderately active women. Nine women using OC and nine control women performed a maximal effort treadmill protocol. Comparison of the resting parameters revealed higher plasma FbDP, plasminogen, alpha 2-antiplasmin and protein C concentrations, and lower PAI activity in the OC group. No differences were observed in plasma concentrations of t-PA antigen, t-PA activity, PAI antigen, antithrombin III, and protein S. Acute maximal exercise resulted in significant increases in t-PA antigen, t-PA activity, t-PA/PAI complexes, and FbDP in both groups of subjects, while PAI activity was reduced. No significant differences were found for the change in those parameters between control and OC users. Exercise induced no variation in any of the groups for PAI antigen, alpha 2-antiplasmin, plasminogen, protein C, or protein S. Our data suggest that changes in the fibrinolytic system induced by physical exercise are not affected by oral contraceptives.

Proteolytic processing of von Willebrand factor subunit: heterogeneity in type-IIA von Willebrand disease.

Type IIA von Willebrand disease (vWD) is a heterogeneous disorder for which two different pathogenetic mechanisms have been proposed: increased proteolytic susceptibility of von Willebrand factor (vWF), and/or interference of its post-translational processing. Subunit analysis of vWF in type-IIA vWD has revealed an increased relative proportion of the 176- and 140-kDa subunit-derived fragments, suggesting an augmented fragmentation of vWF, even in the resting state. We analyzed the subunit pattern of vWF in plasma from five previously described patients with type-IIA vWD. All of them showed the above-mentioned pattern. In addition, the presence of a new band with an apparent molecular mass of 200 kDa, not described in normal individuals or in patients with vWD, was repeatedly observed in one of these patients. This patient also exhibited an abnormal vWF multimeric structure in platelets and in plasma, before and after desmopressin administration, when the blood was collected either in the presence or in the absence of proteinase inhibitors. We believe that an abnormal primary structure of vWF could be responsible for this abnormal proteolytic fragmentation pattern, as well as for the abnormal multimerization of vWF. Moreover, an abnormal susceptibility to proteolysis appears to be present, as suggested by the increase in the relative proportion of the 176-kDa fragment observed in the same patient. Future sequencing studies and genetic analysis may clarify whether there are one or two different defects related to the vWF of that patient. Our results indicate that the subunit analysis of vWF may reveal additional defects present in type-IIA vWD that may help our understanding of the pathogenesis of such disease.

Changes of the fibrinolytic system in liver dysfunction: role of portal hypertension.

The contribution of hemodynamic changes to the pathogenesis of accelerated fibrinolysis in liver disease was investigated in rats. In animals with hepatic lesions induced by a 7-week inhalation of carbon tetrachloride there was a significant increase in blood t-PA activity and PAI activity, with no significant change in portal pressure. Following a 10-min portal vein occlusion there was a marked increase in portal pressure and t-PA activity and a significant decrease in PAI activity. Following ligation of both portal vein and hepatic artery, t-PA activity increased to a higher extent and PAI activity was reduced to a lesser extent than changes found in portal-stenosed rats. Our data suggest that high t-PA circulating levels in liver disease could be related not only to the reduced t-PA clearance as a consequence of liver injury but also to hemodynamic changes.

Changes in the fibrinolytic system associated with physical conditioning.

The effects of physical conditioning on plasma fibrinolytic activity were studied in two groups of subjects. Volunteers not engaged in any sport were compared with individuals having been subjected to aerobic conditioning (middle-distance runners, defined as men running more than 80 km per week). Plasma concentrations of the different components of the fibrinolytic system were evaluated before and immediately after a maximal effort treadmill protocol. Comparison of the resting parameters revealed that under basal conditions for plasma concentrations of plasminogen, fibrinogen, alpha 2-antiplasmin, protein C and protein S there were no differences between the two groups. Concentrations of the fibrin degradation products (FbDP) and fibrinogen degradation products (FgDP) were significantly higher in the runners than in the control group, indicating an increased fibrinolytic potential that seemed to be a consequence of the reduced formation of tissue plasminogen activator-plasminogen activator inhibitor (t-PA-PAI) complexes. Acute maximal exercise resulted in pronounced fibrinolysis, evidenced by the elevation of FbDP and FgDP concentrations, in both groups of subjects. The acceleration of the fibrinolytic activity was larger in conditioned individuals, which could be accounted for by a higher t-PA release and reduced formation of t-PA-PAI complexes when compared to the untrained subjects.

Inhibition of fibrinolysis by cellular glutathione depletion in the rabbit.

The effect of cellular glutathione depletion on fibrinolytic activity in the arterial wall and on the levels of components of the plasma fibrinolytic system was studied in rabbits. Intraperitoneal administration of buthionine sulphoximine (4.5 mmol/kg body wt), an inhibitor of gamma-glutamyl cysteine synthetase, induced a significant reduction in liver glutathione concentrations with a peak decrease of 51% at 7 hours and a progressive return to normal values. The glutathione concentration in aortic tissue was also significantly reduced 7 h after administration of the depleting agent. Fibrinolytic activity in the arterial wall was inhibited following buthionine sulphoximine administration and only reappeared at 24 hours postinjection. Diethyl maleate administration (3.2 mmol/kg body wt i.p.) also depleted liver and aortic glutathione and inhibited fibrinolysis in the arterial wall. Treatment with both glutathione-depleting agents induced a significant reduction in the functional activity of tissue plasminogen activator (t-PA) (-61% and -27% respectively for buthionine sulphoximine or diethyl maleate) and a significant increase in that of plasminogen activator-inhibitor (PAI) (+61% and +27% respectively), while alpha-2-antiplasmin activity was not modified. Our data suggest a modulatory role of glutathione in the release and/or clearance of the components of the fibrinolytic system in the rabbit.

Spontaneous atherosclerotic lesions and prostacyclin formation in rabbits: effects of combined dipyridamole and aspirin.

The influence of dipyridamole and lysine acetylsalicylate on the incidence of atherosclerotic lesions and on arterial prostacyclin formation was studied in rabbits. Male New Zealand rabbits received i.m. for 16 months dipyridamole (12.5 mg/kg/day) and lysine acetylsalicylate (0.5 mg/kg/day). The incidence of spontaneous atherosclerotic lesions in the aorta was reduced by 16.4% with respect to untreated animals. Administration of the drugs significantly increased prostacyclin formation with respect to the untreated rabbits both in animals developing (1124 +/- 197 pg/mg/3 min vs 316 +/- 49 pg/mg/3 min) or not developing lesions (499 +/- 40 pg/mg/3 min vs 246 +/- 19 pg/mg/3 min). The observed increase in prostacyclin formation could account for the lowered incidence of atherosclerotic lesions in rabbits receiving the combination of dipyridamole and lysine acetylsalicylate.

von Willebrand disease type IIC with different abnormalities of von Willebrand factor in the same sibship.

A family with von Willebrand disease has been identified in which different members of the same sibship exhibit different abnormalities of von Willebrand factor (vWF). The two most severely affected sibs (bleeding time over 20 min) had abnormalities of vWF similar to those seen in type IIC. The smallest detectable multimer was increased and the triplet structure of individual multimers was replaced with a single band. The largest multimers could not be detected and there were relatively more small multimers than intermediate sized forms. vWF antigen (vWF:Ag) was decreased to 12.5-17% by electroimmunoassay (EIA) and to 3.2-5.5% by immunoradiometric assay (IRMA). In the less severely affected sibling (bleeding time 12.5 min) there was a similar relative increase in the smallest detectable multimer. However, the larger multimers were present and the relative concentration of large to small multimers was similar to normal. The triplet structure was altered in that the relative proportion of satellite bands to the central predominant band was decreased. vWF:Ag concentrations were moderately decreased (40-80% by EIA and 25-35% by IRMA). The father and grandfather showed a vWF multimeric pattern similar to the less severely affected sibling but there was no decrease in vWF:Ag concentration and their bleeding times were normal. These observations suggest that the interplay of several genetic factors is responsible for the expression of von Willebrand disease in this family.

Fibrinogen Logroño. A new case of congenital dysfibrinogenemia.

An abnormal fibrinogen was discovered in a 9-year-old male subject without history of hemorrhagic diathesis. Coagulation time, prothrombin time and Reptilase time were prolonged. The thrombin time was corrected using increasing concentrations of normal plasma and bovine thrombin; there was a partial correction at pH 6.5 and ionic strength 0.05. A study of the family showed that the mother and a brother of the propositus presented the same abnormalities. Analysis of the purified fibrinogen showed normal fibrinopeptide release and normal levels of sialic acid and hexosamines. However, coagulation index, polymerization of fibrin monomers, isoelectric point and sedimentation coefficient were abnormal. In view of the abnormalities described and by comparison with the data reported in the literature, we believe that this should be considered a new variant of the fibrinogen molecule and we have designated it 'fibrinogen Logroño'.